JP2014201657A - Anisotropic conductive film, connection method, and joined body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anisotropic conductive film or the like, with which warpage of a substrate is prevented and excellent connection reliability is obtained.SOLUTION: An anisotropic conductive film anisotropically and electroconductively connects a terminal of a substrate and a terminal of an electronic component to each other, and contains a film-forming resin, a curable resin, a curing agent, carboxy group-containing acrylic rubber, and electroconductive particles. The carboxy group-containing acrylic rubber has a glass-transition temperature of 18°C or less, and has weight average molecular weight of 75,000 or more.

Description

  The present invention relates to an anisotropic conductive film, a connection method, and a joined body.

  Conventionally, as a means for connecting an electronic component to a substrate, a tape-like connection material in which a thermosetting resin in which conductive particles are dispersed is applied to a release film (for example, anisotropic conductive film (ACF)) ) Is used.

  This anisotropic conductive film starts, for example, when connecting a terminal of a flexible printed circuit (FPC) or IC (Integrated Circuit) chip and an electrode formed on a glass substrate of an LCD (Liquid Crystal Display) panel. In other words, it is used when various terminals are bonded and electrically connected.

  In recent years, there has been a problem that the substrate is warped after the connection between the substrate and the electronic component due to the thinning of the substrate connected by the anisotropic conductive film and the expansion of the use area of the substrate. When the substrate warps, for example, color unevenness occurs in an LCD panel.

In order to reduce the warpage of the substrate, it has been proposed to relax the stress applied to the substrate.
For example, in an anisotropic conductive film obtained from a thermosetting acrylic resin composition, the composition contains at least (A) a thermosetting agent, (B) a thermosetting component, and (C) an acrylic rubber containing a hydroxyl group, (D) Weight of acrylic rubber containing organic fine particles and (E) conductive particles, (B) thermosetting component containing (b1) phosphorus-containing acrylic acid ester and (C) hydroxyl group An anisotropic conductive film having an average molecular weight of 1 million or more and (d1) polybutadiene-based fine particles has been proposed as the (D) organic fine particles (see, for example, Patent Document 1).
In the anisotropic conductive film, acrylic rubber is used for various purposes such as improvement of adhesion (see, for example, Patent Documents 2 and 3). Since the acrylic rubber is a rubber material, it can be expected to relieve stress.
However, when a material that relieves stress, such as the acrylic rubber, is used for the anisotropic conductive film, there is usually a problem that connection reliability is lowered.

  Therefore, an anisotropic conductive film that can prevent warping of the substrate and obtain excellent connection reliability, a connection method using the anisotropic conductive film, and a bonded body using the anisotropic conductive film It is the present situation that provision is demanded.

JP 2008-274019 A JP 2007-80522 A International Publication No. 2001/82363 Pamphlet

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention uses an anisotropic conductive film that can prevent warping of the substrate and obtain excellent connection reliability, a connection method using the anisotropic conductive film, and the anisotropic conductive film. It is an object to provide a bonded body.

Means for solving the problems are as follows. That is,
<1> An anisotropic conductive film for anisotropically conductively connecting a terminal of a substrate and a terminal of an electronic component,
Contains a film-forming resin, a curable resin, a curing agent, a carboxyl group-containing acrylic rubber, and conductive particles,
An anisotropic conductive film, wherein the carboxyl group-containing acrylic rubber has a glass transition temperature of 18 ° C. or lower and a weight average molecular weight of 75,000 or higher.
<2> The acid value of the carboxyl group-containing acrylic rubber is 5 mgKOH / g to 40 mgKOH / g, the glass transition temperature is -30 ° C to 15 ° C, and the weight average molecular weight is 100,000 to 900,000 <1>. The anisotropic conductive film according to 1>.
<3> The <1>, wherein the content of the carboxyl group-containing acrylic rubber is 1% by mass to 15% by mass with respect to the total of the film-forming resin, the curable resin, the curing agent, and the carboxyl group-containing acrylic rubber. To <2>.
<4> A connection method for anisotropic conductive connection between a terminal of a substrate and a terminal of an electronic component,
A first disposing step of disposing the anisotropic conductive film according to any one of <1> to <3> on a terminal of the substrate;
A second disposing step of disposing the electronic component on the anisotropic conductive film such that a terminal of the electronic component is in contact with the anisotropic conductive film;
And a heating and pressing step of heating and pressing the electronic component with a heating and pressing member.
<5> A substrate having terminals, an electronic component having terminals, and an anisotropy interposed between the substrate and the electronic component to electrically connect the terminal of the substrate and the terminal of the electronic component A cured product of a conductive film,
The anisotropic conductive film is the anisotropic conductive film according to any one of <1> to <3>.

  According to the present invention, the anisotropic conductive film capable of solving the above-described problems and achieving the object, preventing the warpage of the substrate, and obtaining excellent connection reliability, and the anisotropic A connection method using a conductive conductive film and a joined body using the anisotropic conductive film can be provided.

FIG. 1 is a schematic diagram for explaining a method of measuring the amount of warpage.

(Anisotropic conductive film)
The anisotropic conductive film of the present invention contains at least a film-forming resin, a curable resin, a curing agent, a carboxyl group-containing acrylic rubber, and conductive particles, and further contains other components as necessary. contains.
The anisotropic conductive film is an anisotropic conductive film that connects a terminal of a substrate and a terminal of an electronic component in an anisotropic conductive connection.

<Film forming resin>
There is no restriction | limiting in particular as said film formation resin, According to the objective, it can select suitably, For example, phenoxy resin, unsaturated polyester resin, saturated polyester resin, urethane resin, butadiene resin, polyimide resin, polyamide resin, polyolefin Resin etc. are mentioned. The film forming resin may be used alone or in combination of two or more. Among these, phenoxy resin is preferable from the viewpoint of film forming property, processability, and connection reliability.
Examples of the phenoxy resin include a resin synthesized from bisphenol A and epichlorohydrin.
As the phenoxy resin, an appropriately synthesized product or a commercially available product may be used.
There is no restriction | limiting in particular as content of the said film formation resin, According to the objective, it can select suitably.

<Curable resin>
There is no restriction | limiting in particular as said curable resin, According to the objective, it can select suitably, For example, an epoxy resin, an acrylate resin, etc. are mentioned.

-Epoxy resin-
There is no restriction | limiting in particular as said epoxy resin, According to the objective, it can select suitably, For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, those modified epoxy resins, alicyclic type An epoxy resin etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

-Acrylate resin-
The acrylate resin is not particularly limited and can be appropriately selected depending on the purpose. For example, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylol Propane triacrylate, dimethylol tricyclodecane diacrylate, tetramethylene glycol tetraacrylate, 2-hydroxy-1,3-diaacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2, 2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloxyethyl) i Cyanurates, such as urethane acrylate, and the like. These may be used individually by 1 type and may use 2 or more types together.
Moreover, what made the said acrylate into the methacrylate is mentioned, These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as content of the said curable resin, According to the objective, it can select suitably.

<Curing agent>
There is no restriction | limiting in particular as said hardening | curing agent, According to the objective, it can select suitably, For example, imidazoles, an organic peroxide, an anionic hardening | curing agent, a cationic hardening | curing agent etc. are mentioned.
Examples of the imidazoles include 2-ethyl 4-methylimidazole.
Examples of the organic peroxide include lauroyl peroxide, butyl peroxide, benzyl peroxide, dilauroyl peroxide, dibutyl peroxide, peroxydicarbonate, and benzoyl peroxide.
Examples of the anionic curing agent include organic amines.
Examples of the cationic curing agent include a sulfonium salt, an onium salt, and an aluminum chelating agent.

  The combination of the curable resin and the curing agent is not particularly limited and may be appropriately selected depending on the purpose. The combination of the epoxy resin and the cationic curing agent, the acrylate resin and the organic A combination with a peroxide is preferred.

<Carboxyl group-containing acrylic rubber>
The carboxyl group-containing acrylic rubber is not particularly limited as long as it has a glass transition temperature of 18 ° C. or lower and a weight average molecular weight of 75,000 or higher, and can be appropriately selected according to the purpose.

The carboxyl group-containing acrylic rubber is an acrylic rubber having a carboxyl group.
The acrylic rubber is, for example, a structural unit derived from monomers such as acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, carboxyl group-containing acrylic acid ester, carboxyl group-containing methacrylic acid ester, and derivatives thereof. Is a polymer containing
Examples of the acrylic rubber include rubbers mainly composed of acrylic acid esters.
Examples of the comonomer constituting the polymer include acrylic acid, methacrylic acid, butyl acrylate, butyl methacrylate, ethyl acrylate, ethyl methacrylate, methyl acrylate, methyl methacrylate, and acrylonitrile.
The carboxyl group in the carboxyl group-containing acrylic rubber may be a carboxyl group derived from acrylic acid and methacrylic acid, or may be a carboxyl group derived from another carboxyl group-containing copolymer monomer. Examples of the other carboxyl group-containing copolymer monomers include 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl phthalic acid, and 2-acryloyloxy. Examples thereof include ethyl hexahydrophthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid, itaconic acid, fumaric acid, maleic acid and the like.

There is no restriction | limiting in particular as an acid value of the said carboxyl group-containing acrylic rubber, Although it can select suitably according to the objective, 3 mgKOH / g or more are preferable, 3 mgKOH / g-40 mgKOH / g are more preferable, 5 mgKOH / g -40 mgKOH / g is more preferable, and 5 mgKOH / g-30 mgKOH / g is particularly preferable. When the acid value is within the particularly preferable range, it is advantageous in that both prevention of warpage of the substrate and connection reliability can be achieved at a high level.
The acid value can be measured based on, for example, Japanese Industrial Standard “JIS K 2501-2003 Petroleum Products and Lubricating Oil—Neutralization Test Method”.

If the glass transition temperature of the said carboxyl group-containing acrylic rubber is 18 degrees C or less, there will be no restriction | limiting in particular, Although it can select suitably according to the objective, -40 degreeC-15 degreeC is preferable, and -30 degreeC-15 ° C is more preferable, and -30 ° C to 5 ° C is particularly preferable. When the glass transition temperature is within the particularly preferable range, it is advantageous in that both prevention of warpage of the substrate and connection reliability can be achieved at a high level.
The glass transition temperature can be determined using, for example, a theoretical glass transition temperature calculation formula (FOX formula). Specifically, according to the FOX formula (TG Fox, Bull. Am. Physics Soc., Vol. 1, No. 3, page 123 (1956)), each monomer constituting the polymer is used alone. It calculates | requires from following formula (1) using Tgn of a polymer.
1 / Tg = Σ (Wn / Tgn) (1)
In the formula (1), Tgn is the glass transition temperature Tg of the homopolymer of each monomer component, Wn is the weight fraction of each monomer component, and Tg is the glass of the copolymer. Transition temperature. The temperature in the formula (1) is an absolute temperature.

The weight average molecular weight of the carboxyl group-containing acrylic rubber is not particularly limited as long as it is 75,000 or more, and can be appropriately selected according to the purpose, but is preferably 100,000 to 1,000,000. , 000 to 900,000 are more preferable, and 700,000 to 900,000 are particularly preferable. When the weight average molecular weight is within the particularly preferable range, it is advantageous in that both prevention of warpage of the substrate and connection reliability can be achieved at a high level.
The weight average molecular weight can be measured by a gel permeation chromatography (GPC) method. For the measurement, for example, Shodex GPC (manufactured by Showa Denko KK) is used. Standard polystyrene is used to create a calibration curve.

  There is no restriction | limiting in particular as content of the said carboxyl group-containing acrylic rubber, Although it can select suitably according to the objective, The said film formation resin, the said curable resin, the said hardening | curing agent, the said carboxyl group-containing acrylic rubber, 1% by mass to 15% by mass is preferable, 3% by mass to 10% by mass is more preferable, and 3% by mass to 5% by mass is particularly preferable. When the content is within the particularly preferable range, it is advantageous in that both prevention of warpage of the substrate and connection reliability can be achieved at a high level.

<Conductive particles>
There is no restriction | limiting in particular as said electroconductive particle, According to the objective, it can select suitably, For example, a metal particle, a metal covering resin particle, etc. are mentioned.

There is no restriction | limiting in particular as said metal particle, According to the objective, it can select suitably, For example, nickel, cobalt, silver, copper, gold | metal | money, palladium, solder etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.
Among these, nickel, silver, and copper are preferable. These metal particles may be provided with gold or palladium on the surface for the purpose of preventing surface oxidation. Furthermore, you may use what gave the insulating film with the metal protrusion and organic substance on the surface.

The metal-coated resin particles are not particularly limited as long as the surfaces of the resin particles are coated with metal, and can be appropriately selected according to the purpose. For example, the surface of the resin particles is nickel, silver, solder , Particles coated with at least one of copper, gold, and palladium. Furthermore, you may use what gave the insulating film with the metal protrusion and organic substance on the surface. In the case of connection considering low resistance, particles in which the surface of resin particles is coated with silver are preferable.
There is no restriction | limiting in particular as the coating method of the metal to the said resin particle, According to the objective, it can select suitably, For example, an electroless-plating method, sputtering method, etc. are mentioned.
There is no restriction | limiting in particular as a material of the said resin particle, According to the objective, it can select suitably, For example, a styrene- divinylbenzene copolymer, a benzoguanamine resin, a crosslinked polystyrene resin, an acrylic resin, a styrene-silica composite resin etc. Is mentioned.

  The conductive particles only need to have conductivity during anisotropic conductive connection. For example, even if the surface of the metal particle is an insulating film, the conductive particle may be used as long as the particle is deformed during the anisotropic conductive connection and the metal particle is exposed.

There is no restriction | limiting in particular as an average particle diameter of the said electroconductive particle, Although it can select suitably according to the objective, 1 micrometer-50 micrometers are preferable, 2 micrometers-25 micrometers are more preferable, and 2 micrometers-10 micrometers are especially preferable.
The average particle diameter is an average value of particle diameters measured for 10 conductive particles arbitrarily.
The particle diameter can be measured, for example, by observation with a scanning electron microscope.

<Other ingredients>
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, a silane coupling agent, a filler, a softening agent, a hardening accelerator, anti-aging agent, a coloring agent (a pigment, dye) ), Organic solvents, ion catchers and the like.
There is no restriction | limiting in particular as content of the said other component, According to the objective, it can select suitably.

<Board>
The substrate is not particularly limited as long as it is a substrate that has terminals and is an object of anisotropic conductive connection using the anisotropic conductive film, and can be appropriately selected according to the purpose. , Glass substrates having terminals, plastic substrates having terminals, and the like.
Examples of the glass substrate having the terminal include an ITO (Indium Tin Oxide) glass substrate, an IZO (Indium Zinc Oxide) glass substrate, and other glass pattern substrates. Among these, an ITO glass substrate and an IZO glass substrate are preferable.
There is no restriction | limiting in particular as a material and structure of the plastic substrate which has the said terminal, According to the objective, it can select suitably, For example, the rigid board | substrate which has a terminal, the flexible substrate which has a terminal, etc. are mentioned.

There is no restriction | limiting in particular as average thickness of the said board | substrate, Although it can select suitably according to the objective, 0.1 mm-1.0 mm are preferable, and 0.2 mm-0.8 mm are more preferable.
The said average thickness is an average value at the time of measuring the thickness of arbitrary 10 places of the said board | substrate.

<Electronic parts>
The electronic component is not particularly limited as long as the electronic component has a terminal and is an object of anisotropic conductive connection using the anisotropic conductive film, and can be appropriately selected according to the purpose. Examples thereof include IC (Integrated Circuit), TAB (Tape Automated Bonding) tape, and liquid crystal panel. Examples of the IC include a liquid crystal screen control IC chip in a flat panel display (FPD).
There is no restriction | limiting in particular as a shape of the said electronic component, According to the objective, it can select suitably, For example, when it sees from an upper surface, a rectangle, a square, etc. are mentioned.

  The combination of the substrate and the electronic component is not particularly limited and may be appropriately selected depending on the purpose. On-glass, COG), Chip-on-Flex (Chip-on-Flex, COF), Flex-on-Board (Flex-on-Board, FOB), Flex-on-Flex (Flex-on-Flex, FOF) The combination of the board | substrate and electronic component which respond | corresponded is mentioned.

  There is no restriction | limiting in particular as average thickness of the said anisotropic conductive film, Although it can select suitably according to the objective, 5 micrometers-100 micrometers are preferable, 10 micrometers-60 micrometers are more preferable, and 15 micrometers-30 micrometers are especially preferable.

  There is no restriction | limiting in particular as a manufacturing method of the said anisotropic conductive film, According to the objective, it can select suitably, For example, the said film formation resin, the said curable resin, the said hardening | curing agent, and the said carboxyl group containing acrylic rubber And a method of applying an anisotropic conductive composition obtained by mixing the conductive particles to a release-treated polyethylene terephthalate (PET) film.

(Connection method)
The connection method of the present invention includes at least a first arrangement step, a second arrangement step, and a heating and pressing step, and further includes other steps as necessary.
The connection method is a method in which the terminals of the substrate and the terminals of the electronic component are anisotropically conductively connected.

  There is no restriction | limiting in particular as said board | substrate and said electronic component, According to the objective, it can select suitably, For example, the said board | substrate illustrated by description of the said anisotropic conductive film of this invention, and the said electronic component are Each is listed.

<First arrangement step>
The first disposing step is not particularly limited as long as it is a step of disposing the anisotropic conductive film of the present invention on the terminal of the substrate, and can be appropriately selected according to the purpose.

<Second arrangement step>
The second placement step is not particularly limited as long as it is a step of placing the electronic component on the anisotropic conductive film so that terminals of the electronic component are in contact with the anisotropic conductive film, It can be appropriately selected according to the purpose.

<Heat pressing process>
The heating and pressing step is not particularly limited as long as it is a step of heating and pressing the electronic component with a heating and pressing member, and can be appropriately selected according to the purpose.
Examples of the heating and pressing member include a pressing member having a heating mechanism. Examples of the pressing member having the heating mechanism include a heat tool.
There is no restriction | limiting in particular as temperature of the said heating, Although it can select suitably according to the objective, 100 to 180 degreeC is preferable.
There is no restriction | limiting in particular as the pressure of the said press, Although it can select suitably according to the objective, 0.5 MPa-100 MPa are preferable.
There is no restriction | limiting in particular as time of the said heating and a press, Although it can select suitably according to the objective, 0.5 second-10 second are preferable.

(Joint)
The joined body of the present invention includes at least a substrate, an electronic component, and a cured product of an anisotropic conductive film, and further includes other members as necessary.

  There is no restriction | limiting in particular as said board | substrate and said electronic component, According to the objective, it can select suitably, For example, the said board | substrate illustrated by description of the said anisotropic conductive film of this invention, and the said electronic component are Each is listed.

The anisotropic conductive film is the anisotropic conductive film of the present invention.
The cured product of the anisotropic conductive film is interposed between the substrate and the electronic component to electrically connect the terminal of the substrate and the terminal of the electronic component.

  The joined body can be manufactured, for example, by the connection method of the present invention.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Production Examples 1-15)
<Carboxyl group-containing acrylic rubber No. Synthesis of 1-15>
(Meth) acrylic acid ester monomer and 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid etc. ) Acrylic acid ester and water are mixed at a predetermined mixing mass ratio so that the resulting acrylic rubber has the desired acid value and glass transition temperature, charged into the reaction vessel, and sufficiently purged with nitrogen while stirring. Went. Next, polymerization was performed by supplying a predetermined amount of peroxide (initiator) to the mixture so that the resulting acrylic rubber had a desired weight average molecular weight.

  Tables 1 to 4 show the acid value, glass transition temperature, and weight average molecular weight of the synthesized carboxyl group-containing acrylic rubber. The acid value, glass transition temperature, and weight average molecular weight were determined as follows.

<Acid value>
The acid value was measured based on Japanese Industrial Standard “JIS K 2501-2003 Petroleum Products and Lubricating Oil—Neutralization Value Test Method”.

<Glass transition temperature>
The glass transition temperature (Tg) was determined using a theoretical glass transition temperature calculation formula (FOX formula).
Specifically, according to the FOX formula (TG Fox, Bull. Am. Physics Soc., Vol. 1, No. 3, p. 123 (1956)), the single weight of each monomer constituting the polymer is determined. It calculated | required from following formula (1) using Tgn of coalescence.
1 / Tg = Σ (Wn / Tgn) (1)
In the formula (1), Tgn is the glass transition temperature Tg of the homopolymer of each monomer component, Wn is the weight fraction of each monomer component, and Tg is the glass of the copolymer. Transition temperature. The temperature in the formula (1) is an absolute temperature.

<Weight average molecular weight>
The weight average molecular weight was measured by a gel permeation chromatography (GPC) method. For the measurement, Shodex GPC (manufactured by Showa Denko KK) was used. Standard polystyrene was used for preparing a calibration curve.

Example 1
<Preparation of anisotropic conductive film>
Phenoxy resin (trade name: YP-50, manufactured by Nippon Steel Chemical Co., Ltd., film forming resin), bisphenol A type epoxy resin (trade name: EP-828, manufactured by Mitsubishi Chemical Corporation, curable resin), silane coupling Agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), cationic curing agent (trade name: SI-60L, manufactured by Sanshin Chemical Industry Co., Ltd.), and carboxyl group-containing acrylic rubber obtained in Production Example 1 No. 1 was mixed by the compounding quantity shown in Table 1, and the composition was obtained. Conductive particles (trade name: AUL704, manufactured by Sekisui Chemical Co., Ltd.) were dispersed in the obtained composition to obtain an anisotropic conductive composition. Dispersion was performed such that the particle density of the conductive particles in the obtained anisotropic conductive film was 50,000 particles / mm ² .
The obtained anisotropic conductive composition was applied on a polyethylene terephthalate film so as to have an average thickness of 20 μm to obtain an anisotropic conductive film.

<Manufacture of joined body and evaluation of joined body>
The joined body was manufactured by the following method and evaluated as follows. The results are shown in Table 1.
An ITO wiring board having an average thickness of 0.5 mm on which an ITO (Indium Tin Oxide) film was patterned was used as the glass substrate.
An IC chip (1.8 mm × 20 mm, t (thickness) = 0.5 mm, Au-plated bump 30 μm × 85 μm, h (height) = 15 μm) was used as the electronic component.
The anisotropic conductive film was slit to a predetermined width and attached to the ITO wiring board. After temporarily fixing the IC chip thereon, a heat tool coated with Teflon (registered trademark) with an average thickness of 50 μm was used as a buffer material, and bonding was performed at a bonding condition of 160 ° C.-60 MPa-5 sec. Completed.

<< Connection reliability (conducting resistance) >>
The initial resistance value of the obtained bonded body and the resistance value after a 500-hour TH test (Thermal Humidity Test) at 85 ° C. and 85% RH were measured by the following methods. The results are shown in Table 1.
Using a digital multimeter (product number: digital multimeter 7555, manufactured by Yokogawa Electric Corporation), a resistance value was measured when a current of 1 mA was passed by the four-terminal method.

<< Warpage amount >>
A stylus type surface roughness meter (trade name: SE-3H, manufactured by Kosaka Laboratory Ltd.) was used for measuring the amount of warpage. As shown in FIG. 1, the bonded body is bonded so that the surface of the glass substrate 1 to which the electronic component 3 is not connected by the cured product 2 of the anisotropic conductive film faces upward and the plane of the glass substrate 1 is horizontal. I put my body. And as shown in FIG. 1, the surface of the glass substrate 1 on the opposite side to the surface where the electronic component 3 was connected was scanned with the stylus 4 of the stylus type surface roughness meter. The stylus 4 scans the surface in the longitudinal direction of the electronic component 3 at a distance of 20 mm from a location where one side of the electronic component 3 is located to a location where the other side facing the one side is located. did. Then, the displacement in the vertical direction at the time of scanning with the stylus 4 was measured and used as the amount of warpage. The amount of warpage was measured for 10 samples, and the amount of warpage was determined from the average value. The results are shown in Table 1.
When the warp is convex, the amount of warp is expressed as a positive number, and when the warp is concave, the amount of warp is expressed as a negative number.

(Examples 2 to 24 and Comparative Examples 1 to 3)
In Example 1, an anisotropic conductive film was produced in the same manner as in Example 1 except that the composition of the anisotropic conductive composition was changed to the composition shown in Tables 1 to 4.
About the obtained anisotropic conductive film, evaluation similar to Example 1 was performed. The results are shown in Tables 1 to 4.

The relative proportions of the blending amounts in Tables 1 to 4 coincide with the relative proportions of the contents of the respective components in the anisotropic conductive film.
The film forming resin used in Example 22 is Epicoat 1256 (manufactured by Nippon Steel Chemical Co., Ltd.).
The curable resin used in Example 23 is YD-128 (manufactured by Mitsubishi Chemical Corporation).
The curing agent used in Example 24 is SI-100L (manufactured by Sanshin Chemical Industry Co., Ltd.).

In Examples 1 to 24, the amount of warpage of the substrate is 15.0 μm or less, and the conduction resistance after 500 hours at 85 ° C. and 85% RH is 10.0Ω or less, which is excellent in preventing the warpage of the substrate. Connection reliability was compatible.
In particular, the acid value of the carboxyl group-containing acrylic rubber is 5 mg KOH / g to 30 mg KOH / g, the glass transition temperature is −30 ° C. to 5 ° C., the weight average molecular weight is 700,000 to 900,000, and the carboxyl group-containing acrylic rubber When content is 3 mass%-5 mass% with respect to the sum total of film forming resin, curable resin, a hardening | curing agent, and carboxyl group-containing acrylic rubber, the curvature amount of a board | substrate is 13.0 micrometers or less. In addition, the conduction resistance after 500 hours at 85 ° C. and 85% RH was 5.0Ω or less, and both the prevention of the warpage of the substrate and the connection reliability were highly compatible (for example, Examples 2 to 6). 10, 12).
On the other hand, when the glass transition temperature of the carboxyl group-containing acrylic rubber is 20 ° C. (Comparative Example 1), the weight average molecular weight is 50,000 (Comparative Example 2), or the anisotropic conductive film is a carboxyl group-containing acrylic rubber. When not included (Comparative Example 3), the warpage of the substrate is more than 15.0 μm, and the conduction resistance after 500 hours at 85 ° C. and 85% RH is at least one of more than 10.0Ω. It was not possible to achieve both prevention of connection and excellent connection reliability.

  The anisotropic conductive film of the present invention can be suitably used for connection between a substrate and an electronic component because warpage of the substrate can be prevented and excellent connection reliability can be obtained.

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Cured material of anisotropic conductive film 3 Electronic component 4 Stylus

Claims (5)

An anisotropic conductive film for anisotropic conductive connection between a terminal of a substrate and a terminal of an electronic component,
Contains a film-forming resin, a curable resin, a curing agent, a carboxyl group-containing acrylic rubber, and conductive particles,
An anisotropic conductive film, wherein the carboxyl group-containing acrylic rubber has a glass transition temperature of 18 ° C. or lower and a weight average molecular weight of 75,000 or higher.   The acid value of the carboxyl group-containing acrylic rubber is 5 mgKOH / g to 40 mgKOH / g, the glass transition temperature is -30 ° C to 15 ° C, and the weight average molecular weight is 100,000 to 900,000. An anisotropic conductive film.   The content of the carboxyl group-containing acrylic rubber is 1% by mass to 15% by mass with respect to the total of the film-forming resin, the curable resin, the curing agent, and the carboxyl group-containing acrylic rubber. An anisotropic conductive film according to any one of the above. A method of connecting anisotropically conductively connecting a terminal of a substrate and a terminal of an electronic component,
A first disposing step of disposing the anisotropic conductive film according to any one of claims 1 to 3 on a terminal of the substrate;
A second disposing step of disposing the electronic component on the anisotropic conductive film such that a terminal of the electronic component is in contact with the anisotropic conductive film;
And a heating and pressing step of heating and pressing the electronic component with a heating and pressing member. A substrate having a terminal; an electronic component having a terminal; and an anisotropic conductive film that is interposed between the substrate and the electronic component and electrically connects the terminal of the substrate and the terminal of the electronic component. A cured product,
The joined body, wherein the anisotropic conductive film is the anisotropic conductive film according to claim 1.